# Table 11: KAOPEN Spline — Z₁ Effect Below vs Above Knot

| Knot (pctl) | KAOPEN value | Z₁ below | p-val | Z₁ above | p-val | R² |
|---|---|---|---|---|---|---|
| p25 | -1.25 | -1.20** | 0.0229 | 0.32*** | 0.0090 | 0.2712 |
| p50 | 0.19 | -0.30 | 0.1866 | 0.79*** | 0.0014 | 0.2741 |
| p75 | 2.28 | 0.21* | 0.0690 | -0.00*** | 0.0000 | 0.2725 |